The ductility of a large copper (k = 386 W/mºC, a = must be increased by quenching before it can be extruded. The copper slab is first heated up to have a uniform initial temperature of 1,000 °C. Cold water is then sprayed onto one side of the slab to maintain a constant surface temperature of 20 °C. (a) Draw a simple sketch to show the change of temperature inside the slab with time. (b) Calculate the temperature (in °C) at 10 cm below the surface 20 seconds after the surface temperature is lowered. (c) Calculate the heat transfer flux rate (kW/m2 ) through a plane 8 cm below the surface 15 seconds after the surface temperature is lowered. (d) Calculate the total heat removed by cold water from the surface in the first 5 seconds (J/m2_). 11.234 x10-5 m 2 /s, p = 8.954 g/cm3) slab

The ductility of a large copper (k = 386 W/mºC, a = must be increased by quenching before it can be extruded. The copper slab is first heated up to have a uniform initial temperature of 1,000 °C. Cold water is then sprayed onto one side of the slab to maintain a constant surface temperature of 20 °C. (a) Draw a simple sketch to show the change of temperature inside the slab with time. (b) Calculate the temperature (in °C) at 10 cm below the surface 20 seconds after the surface temperature is lowered. (c) Calculate the heat transfer flux rate (kW/m2 ) through a plane 8 cm below the surface 15 seconds after the surface temperature is lowered. (d) Calculate the total heat removed by cold water from the surface in the first 5 seconds (J/m2_). 11.234 x10-5 m 2 /s, p = 8.954 g/cm3) slab

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter3: Transient Heat Conduction

Section: Chapter Questions

Problem 3.3P

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